CARLSBAD - Before a crowd of 20 people in the morning and nearly 40 in the evening, the state's Public Utilities Commission unveiled proposals to change the 760 area code Wednesday.

The business people, city government representatives and retired folks who commented on the presentations all shared one view: They don't want their 760 area code to change.

"All 550 of us don't want to lose our area code," said Chuck Rabel, who represented the members of the Vista Chamber of Commerce.

Mike McReynolds, owner of small construction company in Vista, said he had experienced a series of area code changes in recent years and still has stacks of old business cards and stationary made useless after the last change.

"I lost $50,000 to $100,000 in business in the last area code change, and I'm not a rich guy," he said.

The 760 area code currently covers a vast expanse of Southern California, including North County, El Centro and Palm Springs. The extreme northeastern edge of the 760 border reaches well north of the Mammoth Lakes area.

Officials say the region's rapid population growth has had an effect on the telephone system. By fall 2009, the commission forecasts that it will have exhausted the number of available phone prefixes in the 760 area code, said Sue Wong, a regulatory analyst.

Because of this, the commission is considering "overlaying" a new area code across the existing 760 region or splitting the region into two parts and giving each its own area code. There are benefits and downsides to each option, Wong said.

An area code overlay, which currently exists in California only in Los Angeles, would allow existing phone customers to keep 760.

New customers would get a 442 area code. The downside? Everyone would have to punch in the full area code every time they wanted to make a phone call, even if the person they are calling is just down the street, Wong said.

The other option would be to split the area code. The commission has released maps showing two different ways to divide the vast region; both versions put all of North County on one side of the line. One version has the El Centro region on the same side of the line as North County; the other makes the San Diego County limits the dividing line.

Which side would get a new area code and which one might keep the 760 hasn't been settled, commission officials said. A decision on the future of 760 is expected by the end of the year, and changes would go into effect by mid-2009, officials said.

Representatives for several North County city governments told the commission during the morning meeting that they wanted more information about the overlay option, but many residents and business people who attended the evening session preferred splitting the area code in two.

"The overlay should be a nonstarter," the Vista Chamber of Commerce representative said. "I don't even know why you would consider it. Nobody wins."

Everybody appeared to agree on one thing: If the area code is split, they think people on the eastern side of the line should get the new 442 area code while North County keeps 760.

"We would prefer that our area code be preserved," said Vista's representative, Jenny Peterson.

The eastern part of the 760 area code is where the growth is going to come in the next decade, so it makes sense to give them a new area code, said Karl Schwarm, director of Housing and Neighborhood Services for San Marcos. That city and Carlsbad are getting close to build-out - the point where little undeveloped land remains, he noted.

Carlsbad resident Stuart Barasch said he thought that North County households are more likely to have multiple phone lines and that "might not be the case in some of the rural areas" to the east. But a consultant for the commission said that the area with the most growth in recent telephone service requests is the eastern region, and he said that people on both sides of the dividing line want to keep the 760 area code.

One of the few people in the evening session who liked the overlay proposal was Poway resident Doug Munson, who runs a Carlsbad-based telecommunications business. He said people might as well get used to dialing more numbers now because eventually they're going to have to do so given the increasing number of telephone service requests.

Joe Cocke, a planner with the consulting company who is helping the commission with the area code proposals, said the goal is to "make sure that the areas that change won't have to change again for eight to 10 years."

Under the two split proposals, North County's area code wouldn't change again for at least 15 years, he said. The region's most recent area code change was a decade ago, he said.

But area business people noted that some ZIP codes have changed in North County recently and they urged the commission to take that into consideration.

For information on the commission's proposals, go to www.cpuc.ca.gov/760areacode.

- Contact staff writer Barbara Henry at (760) 901-4072 or bhenry@nctimes.com.